Japanese Patent Laid-Open No. 2009-145887 discloses a multi-port wavelength switch module. This multi-port wavelength switch module includes a multilayer ceramic base mounting an electronic component thereon; an optical bench mounting an optical component such as a diffraction grating; a MEMS array bonded to the multilayer ceramic base; an enclosure placing them therein; and a fiber feedthrough for introducing a plurality of optical fibers into the enclosure. Note that the optical fibers introduced into the enclosure are optically connected to the optical component mounted on the optical bench.